When buildings are constructed, there may or may not be a detailed plan for the deployment of electrical fixtures in the design schematics. If one does exist, over the course of the construction, the plan may frequently change “on the fly” due to the changing needs of the customer or individual decisions by electricians—while the original plans remain unchanged. When an electrical installation job is complete, typically, an electrician may place a few words on a paper label on the inside cover of electrical service box, notating things like “stove,” “refrigerator,” “2nd floor bedroom” or perhaps “front offices,” but knowing what devices (outlets, switches . . . etc.) are actually connected to a particular circuit or to each other, may remain a mystery—the answer is in a tangle of wires behind the walls or above the ceiling.
When there are problems with electrical service and/or if future work needs to be done within a building, a large amount of time may be invested to figure out how the building is wired. For example, trying to evaluate and diagnose safety problems may be difficult, since knowing how a circuit is laid out could be central to understanding and diagnosing the cause. Additionally, before any electrical rework is completed on a building, it may be important to know how existing devices are connected to one another and to which breakers/circuits they belong.
In addition to the above, with the increasing emphasis on energy costs and efficiency, the ability to properly monitor power usage within a house or building is becoming ever more important. Knowing what devices are connected to a particular circuit, and in fact, how they are connected to one another and physically located within a building may provide much more information about how and where energy is being used. Monitoring power usage and costs may provide building owners and/or occupants a better understanding of how to adjust their usage to reduce both their costs and the load on the power system.